The present invention relates generally to the control of zones or sections of conveyor systems, and, more specifically, in one embodiment, to a method and apparatus for controlling multiple zones of an accumulating conveyor.
Conveyors can be utilized to transport products, parts, cartons, packages, material, or other such items from one location to another. The items can be placed upon conveying elements such as movable rollers or belts which carry the items to their destination.
Accumulating conveyors are conveyors which are divided into a plurality of zones that extend from the inlet end to the exit end. These zones are sections of the conveyor where driving force to move the conveying elements for the zone may be either applied or removed independently of the other zones in the system. Such conveyors are useful in that certain portions of the conveyor can be stopped and started as needed, independent from similar control of other portions. For example, if it is determined that items downstream cannot be removed from the last zone of the conveyor quickly enough, or that certain items are otherwise stopped or jammed in position, the upstream zones can be sequentially stopped to allow items to line up across the conveyor during the delay. Thus, in the case of the failure to timely remove items from the end of the conveyor, a signal can be provided such that the items will not continue moving and thus will not fall off the conveyor and possibly become damaged. Likewise, in the case of a stoppage or jam, a signal can be provided to stop upstream items such that they will not collide with one another and possibly become damaged.
In accumulating conveyors, each zone can be driven by a one or more drive mechanisms, such as motors or the like, to deliver the driving force. In particular, in some accumulating conveyors, a chain is driven by a motor and the driven chain is selectively engageable with the rollers of a given zone. The items to be moved rest upon these rollers.
To move the chain into engagement with the rollers, an actuator or clutch can be selectively moved, such as under the power of a pneumatic valve. For example, a valve can be moved to an open position providing pneumatic pressure to the actuator and causing movement of the actuator and chain toward the rollers and subsequent engagement of the chain and rollers. To disengage the chain and the rollers and to subsequently stop the rollers from moving, such as in the event of a downstream jam or delay, the force can be removed by returning the valve to a closed position, thereby moving the actuator and chain away from-the rollers and thereby disengaging the chain and rollers. Sensors can be utilized to determine whether a stoppage or delay has occurred, and the valves can then be appropriately controlled to stop or drive appropriate zones across the conveyor.
A control module having valves and electronic control circuitry can be utilized for controlling an individual zone of such a conveyor. Each such module can communicate with one or more other modules to determine whether to drive or stop its respective zone. While such modules having electronics and valves can be provided for each zone in the conveyor, the cost of such a system can be high, and the time and complexity in connecting the various modules can be excessive. Accordingly, it is desirable to decrease the cost, components, and/or complexity of controlling accumulating conveyors.
Furthermore, control modules for accumulating conveyors can be provided with programmable features, such as sleep, timer delay, and jam modes for instance. For example, a sleep mode (also referred to as a snooze mode) can be initiated to stop the movement of a zone, if an item has not been present in the zone for a predetermined amount of time. Such a feature can reduce energy usage, minimize wear of moving parts, and/or reduce audible noise. A timer delay can be utilized to delay the deactivation or activation of a zone until a timer has expired, such that throughput can be increased in the event that the condition is quickly removed which would otherwise have caused the deactivation or activation (e.g., by delaying the passing or utilization of a signal from a sensor or from another module). As another example, a jam mode can be initiated to stop upstream zones, if an item is continually sensed in a downstream zone for a predetermined amount of time. Such a feature can prevent collision of items and then resume movement of items once the jam is cleared. However, the accuracy and effectiveness of such features can often depend upon the speed of the conveyor. Accordingly, it is desirable to provide more accurate and effective programmed control of the zones of accumulating conveyors.
It is an advantage of one or more illustrative embodiments of the invention to decrease the cost, components, and/or complexity of controlling accumulating conveyors.
An advantage of one or more illustrative embodiments of the invention is to provide more accurate and effective control of the zones of accumulating conveyors.
In accordance with at least one embodiment of the present invention, a control module is provided for controlling at least two conveyor zones in an accumulating conveyor. The module of this embodiment comprises an input configured to receive a first article detection signal from a first article detection sensor for a first zone in an accumulating conveyor, an input configured to receive a second article detection signal from a second article detection sensor in a second zone of the accumulating conveyor, and an input configured to receive a command signal from another control module. The first zone comprises a plurality of rollers selectively rotatable in unison by a drive mechanism, and the second zone comprises a plurality of rollers selectively rotatable in unison by a drive mechanism. The control module further comprises an output configured to provide a first actuation signal to cause selective rotation of the rollers of the first zone of the conveyor, and an output configured provide a second actuation signal to cause selective rotation of the rollers of the second zone of the conveyor. Moreover, the control module comprises a control circuit receiving the first and second article detection signals and the command signal and configured to independently control the first and second actuation signals based upon the status of the first and second article detection signals and the command signal. In some embodiments, the control module may include a pair of pneumatic valves configured to provide the actuation signals under control of the control circuit, the actuation signals comprising pneumatic signals. Switches can also be included and configured to provide input signals to the control circuit for selecting the mode of operation of the control circuit. Additional similar article detection inputs and actuation outputs can be provided if it is desired to control additional zones with this single control module. For example, the module can be provided with an article detection input and actuation output for three or more zones.
Furthermore, according to at least one embodiment, a control system is provided for an accumulating conveyor having a plurality of independently driven zones. The system comprises an input/output module including an input configured to receive a first article detection signal from a first article detection sensor for a first zone in an accumulating conveyor, and an input configured to receive a second article detection signal from a second article detection sensor in a second zone of the accumulating conveyor. The first zone comprises a plurality of rollers selectively rotatable in unison by a drive mechanism, and the second zone comprises a plurality of rollers rotatable in unison by a single drive mechanism. The input/output module further comprises an output configured to provide a first actuation signal to cause selective rotation of the rollers of the first zone of the conveyor, and an output configured provide a second actuation signal to cause selective rotation of the rollers of the second zone of the conveyor. The system further includes a control module in communication with the input/output module to receive the first and second article detection signals, wherein the control module is configured to control the first and second actuation signals using the status of the first and second article detection signals. In some embodiments, the input/output module can comprise a pair of pneumatic valves configured to provide the actuation signals under control of the control module. Additional similar article detection inputs and actuation outputs can be provided if it is desired to control additional zones with this single control module.
Moreover, in accordance with at least one embodiment, a method is provided for controlling two or more conveyor zones using a single control module. The method comprises receiving in a control module at least one command signal from another control module for controlling the mode of operation of the control module. The method further comprises using a control circuit in the control module to control a first actuation signal for control of a first conveyor zone in response to the command signal. In addition, the method comprises using the control circuit in the control module to control a second actuation signal for control of a second conveyor zone in response to the command signal. In some embodiments, the command signal can comprise at least one of an accumulation and release signal, and the control circuit can receive article detection signals from sensors indicating whether articles are present in two zones of the conveyor
In addition, according to at least one embodiment of the invention, a method is provided for controlling at least one conveyor zone. The method comprises receiving an article detection signal from a zone of a conveyor, and receiving an input signal from a user representing the speed at which the conveyor will run. Moreover, the method comprises using the input signal and the article detection signal to provide an actuation signal for control of a zone of the conveyor.
Moreover, in accordance with at least one embodiment of the invention, a control module is provided for controlling at least one zone of a conveyor. The control module includes an input configured to receive an article detection signal from a zone of a conveyor, and an output configured to provide an actuation signal for control of a zone of the conveyor. The module further comprises a user interface configured to receive an input from a user representing the speed at which the conveyor will run, and a control circuit configured to use the input signal and the article detection signal to set the actuation signal.
In addition, according to at least one embodiment of the invention, a method for controlling a zone of a conveyor using a sleep mode of operation is provided. The method comprises deactivating the present zone of a conveyor based upon the absence of one or more articles in one or more zones of the conveyor. The method further comprises reactivating the present zone of the conveyor as well as at least one downstream zone, based upon the presence of one or more articles in one or more zones of the conveyor.
Still other advantages, aspects, and embodiments of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described details of illustrative embodiments of this invention, simply for the purposes of illustration and describing currently contemplated best modes. As will be realized, other different aspects and embodiments can be provided without departing from the scope of a given claim, and particular aspects, details, embodiments, principles, and advantages mentioned should not be viewed as restricting a given claim. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature and not restrictive in nature.